Speeding through a wide expanse of river in a small boat, surrounded by acres of steamy jungle and with nothing on the horizon but an endless stretch of calm water, it’s easy to imagine you are travelling to the edge of the world. In fact, we were heading to a tiny corner of the Caribbean coast of Costa Rica, called Parismina.

It is a place where sloths hang languidly from branches, crocodile eyes lurk beneath the water and monkeys move noiselessly between creepers.

I was on a two-week trip to Costa Rica with my boyfriend Richard. Armed with just a guide book and Google we organised each part of the trip independently – selecting Parismina as our first stop because it sounded a bit different.

Even getting there was an adventure. It’s accessible only by boat, and is served by one or two stores that open sporadically. But first we had to find the boat. After landing at the capital, San Jose, we hired a 4x4, opened the map and set off.

Boating on the lake in the jungle in Costa Rica

When I phoned our first host Gerardo to tell him we were on our way he said we’d spot him at the port by his ‘white shirt.’ As a city-dwelling office worker, I wasn’t sure about his distinguishing feature.

But after a bumpy off-road ride we arrived at the ‘port’ with its one shop, small, dusty parking lot and one man – Gerardo – with his white shirt and flat-bottomed metal boat. Once aboard, we raced along the river as vast swathes of jungle opened up.

Our first stop was Esmeralda Lodge – three wooden cabins tucked away in the jungle, where you fall asleep to the sound of frogs and wake to the bellow of howler monkeys before birdsong signals breakfast.

The lodge is family-run, with typical Costa Rican meals home -cooked every morning and evening by Gerardo’s mother – dishes such as rice and beans and plantain with fish.

Stunning sight: Volcan Poas

Each cabin was built by Gerardo and his father, they are eco-friendly and house up to four people. Esmerelda Lodge sits in private grounds bordering the beach where you’ll find one of the key draws of this area – the turtle nesting sites.

Parismina is the lesser known cousin of Tortuguero – a sprawling and somewhat dishevelled area famous for turtle watching and conservation. Tours run from both sites but Parismina is smaller and quieter.

We soon found ourselves walking on the beach dressed in black from head to toe (torches aren’t allowed as they scare nesting turtles) searching for any that had come ashore to lay their eggs.

Being the end of the season, we only spotted tracks where green turtles had changed their mind and gone back into the sea, but this area is renowned for nesting Leatherbacks between April and August.

Nature trail: Canopy walkway in the cloudforest

We also went on a boat tour through Tortuguero National Park with Gerardo and his father, who had a talent for spotting sloths in the highest trees, crocodiles and caimans, howler monkeys, lizards on branches and birds including grebes, ­cormorants, snowy egrets, toucans and impressive blue-throated herons.

While relatively small, this Central ­American country is a place of contrasts and after the sweltering shores of Parismina our next stop was Bajos del Toro with its huge, thundering waterfall Catarata del Toro.

This tiny village in the lowlands is considerably wetter and at least 10° cooler than the Caribbean coast.

Its small selection of bars and restaurants have an authentic Costa Rican ­atmosphere. Then there’s the impressive waterfall and surrounding gardens which teem with hummingbirds. It’s also a great base for exploring Volcan Poas – the only active volcano in the country where, on a clear day, you can see its steaming pool of sulphur.

Local life: White faced capuchin monkeys

After a couple of days we made for our next stop – Volcan Arenal. Although only 60 miles away, this felt like another country with higher temperatures and a definite tourist bustle.

The volcano – dormant since 2010 following eruptions in 1998 – dominates the landscape. Its towering summit stands next to Arenal Lake, a fantastic spot for kayaking. Hot springs abound – in both local free spots and in hotels.

Arenal is close to Monteverde’s humid cloud forest where we trekked – on foot and by horse – through jungle. On a night tour we saw tarantulas, sloths and even a porcupine up a tree.

Wildlife lovers must visit Costa Rica’s most famous, but smallest, wildlife park – Manuel Antonio (£10pp to get in) – which is 120 miles south of Monteverde on the Pacific coast.

Just 15 minutes into this coastal jungle we spotted a three-toed sloth coming down from a tree for a toilet break – a lucky sight as their slow digestion means this happens just once a week.

Jungle nook: Esmerelda eco-lodge

We also watched white-faced capuchins and squirrel monkeys swing through the trees over our heads and had our path barred by an iguana.

Manuel Antonio also has a lovely beach where you can spot whales if you’re lucky and a waterfall where we found a poison dart frog and a red eyed tree frog – almost perfectly camouflaged beneath the leaf of a palm tree.

Our final destination was the Pacific coast and the chilled out beaches of Matapalo. Tides are strong and better for surfers than swimmers but the beach stretches for miles and also has a turtle conservation centre, run by volunteers who help newly born turtles to the sea.

With a few lodges and restaurants peppering the unspoilt coastline, this was the perfect place to relax and we found some lovely B&B beach cabins – called Dos Palmas Beach Cabinas – where we were able to watch the sunset from a hammock while listening to the waves.

Travel file

Return Delta flights from Gatwick to San José cost from £500. delta.com

British Airways will operate flights from Gatwick to San Jose starting April 27 2016 with fares from £546 return. ba.com

An eight-day Costa Rica Volcano & Beach Discovery tour with Travelbag costs from £959pp if booked by November 30 including direct flights from Heathrow for travel between May 1 and 30 November 2016. travelbag.co.uk 020 7001 4112

Currency: Costa Rica accepts US dollars and Costa Rican Colones which you should buy there for a better rate.

Top tip: Bring a waterproof. It’s hot but most days see at least one big downpour.

Where to stay: Three nights at Esmeralda Lodge with all meals, transport, a full-day tour and turtle night tour is from £330 for two. esmeraldalodge.com Two nights B&B at Dos Palmas Beach Cabinas is from £65 for two.

Getting around: Rent a Jimny 4x4 for about £380 for two weeks from Wildrider wild-rider.com